The idea for X-men Legends is pure genious, the fact that x-men have been around for awhile alredy gives each character its noticability aswell as give favorites. The idea of character change, lead/ follow allow the player to test each of the mutants distinct abilities aswell as specials, and combos. The idea is simple enough to be an RPG and gets the job done.
Leveling up, is something i've just never seen before for an x-man. The player doesn't start of strong with max powers or speed, but, where'd be the fun in that? In the later levels its kickass to see your favorite team gain exp in the danger room and either learn or foll around however much they want with "simulations",of either enemies (BLOB,PYRO,MYSTIQUE,etc)or one of your own...
If it came down to it, the only really bad thing about legends is the camera angling. It kinda makes everything miniaturized making even characters hard to distinguish. The voices are okay, but some can get anoying evenlike magma, storm or blob. Finally, the graphics are kinda like something outta JetSetRadio(which is okay for some)
An extra, would be the freedom of character training and abilities to effect game surroundings (make bridges,stop fires,crumble walls with brute force and a hell lot more.)